Pathfinder: Wrath of the Righteous allows you to play as a holy Angel. You must unlock the Angel Mythic Path to do this. You can learn how to unlock this Mythic Path below.
The opportunity for this path comes early. As you explore the underground after the city has been attacked, you will come to a fork. Take the left path and you will find Lann and Wenduag, two Mongrelmen.
Lann and Wenduag will explain that they are searching for an angel's sword. Agree to help the pair and they will join your party. Explore the room and you will reveal a pile of rubble that you can interact with. Doing so will reveal the angel's sword. Your character will experience a vision from the perspective of Lariel, an angel in his final moments.
After the vision, your character will grasp the sword, which Lann calls the Light of Heaven. He will urge you to show the sword to his and Wenduag's chief and offers to lead you to their camp. Along the way, Wenduag will ask you not to show the chief the Light of Heaven. Once at the camp, you will have to decide if you want to show the sword to the chief. Choosing to show the Light of Heaven will unlock the Angel Mythic Path.
For more information on Pathfinder: Wrath of the Righteous, check out How to unlock the Lich Mythic Path in Pathfinder: Wrath of the Righteous and How to identify items in Pathfinder: Wrath of the Righteous on Pro Game Guides.